For some reason the very last mission for the samedi is not showing up on my map. i was wondering if this was because i hadnt fufilled certain prerequisites or something like that

It's been a while since I played the game, so I don't really recall any specifics, but have you taken out all of their strongholds?

you need to complete ALL of the Sons of Samdi stronghold missions as well. then the final mission is unlocked

Yeah you need all the strongholds to do the mission. I had this same problem in the original Saints Row.

ahh okay thanks guys ill try that

Savior is here, complete all the Samedi strongholds as said before, the last mission is inside the place, u should see a building nearby, or down some stairs if i remember correctly.. with the Ultor logo on it... the mission start is near there.

I had this same problem, i also used google.